Log Message:
Update sylpheed to 0.8.3

  * The state of compose window is now changed automatically when the
    account is selected.
  * The option to only mark message as read when opened in new window has
    been added.
  * The receive progress dialog now shows detailed information in the
    status list.
  * The receive progress dialog can be kept open.
  * The line-joining problem of auto-wrapping has been fixed.
  * IMAP and News cache files/directores are now correctly purged if
    they become unnecessary.
  * The wrong news article number calculation has been fixed.
  * The summary refresh problem has been fixed.